Determining Body Mass Index

What is body mass index?

Determining how much your adolescent should weigh is not a simple matter of looking at an insurance height-weight chart, but includes considering the amount of bone, muscle, and fat in his/her body's composition. The amount of fat is the critical measurement.

A good indicator of how much fat your adolescent carries is the Body Mass Index (BMI). Although it is not a perfect measure, it gives a fairly accurate assessment of how much of your adolescent's body is composed of fat.

The formulas below apply to adults only. For children and adolescents ages 2 to 19 years, an additional step must be performed after the BMI has been determined using one of the formulas below: the BMI-for-age percentile is determined by comparing your adolescent's weight to that of other adolescents of the same age and sex.

To calculate an adult's BMI using the English formula:

BMI can be calculated using pounds and inches.

BMI = Weight in Pounds x 703(Height in Inches) x (Height in Inches)

For example, a person who weighs 165 pounds and is 5 feet 4 inches tall has a BMI of 28.

165 lbs x 703 = 28(64 inches) x (64 inches)

To calculate an adult's BMI using the Metric formula:

BMI can be calculated using kilograms and meters.

BMI = Weight in Kilograms(Height in Meters) x (Height in Meters)

For example, a person who weighs 99.79 Kilograms and is 1.905 Meters tall has a BMI of 27.5.

99.79 Kg = 27.5(1.905 Meters) x (1.905 Meters)

A BMI between 25 to 29 is considered overweight. Anything over 30 is considered obese.